Feed-valve device



April 15, 1930.

J. B. WRIGHT FEED VALVE DEVICE Filed Jan. 4, 1927 INVENTOR WM! w m R .o www E ,A NWW Patented pr. 125, 193

`UNITED STATES PTENT oFFicE JOHN B. WRIGHT, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO` THE WESTING- HOUSE `AIR :BRAKE COMPANY, OF WILMERDING, PENNSYLVANIA, A CORPORA- TION OF PENNSYLVANIA FEED-VALVE DEVICE Application filed. January 4, 1927. Serial No. 158,933.

` a In the usual feed valve device, means are employed for permitting a flow of fuid at main reservoir pressure from the slide valve side of the supply piston to the opposite side ofsad piston. Said means, in some cases,

" comprise a loose fitting supply piston, which permits fluid to leak through the clearance space between the piston and pistoncylinder. `It has also been proposed to employ a feed valve construction, in which the supply ,pistonis fitted with a piston packing ring to prevent leakage around the piston and to provide a passage in the feed valve casing to connect the opposite sides of the supply piston, said passage containing a choke plug to'restrict the flow of the fluid.

The Huid under pressure in the main reservoir usually containsoil vapor and perhaps other foreign matter, and with either type of feed valve construction described above, said foreign matter tends to collect either when the fluid expands after leaking around the loosely tting piston or after iiowing through the choke in the passage connecting oppositesides of the supply piston. In both cases, the` accumulation` of oil and foreign matter, which is more or less viscous and gummy, effects the operation of the feed valve device by making said operation sluggish or even `causing a failure to operate.

The principal object of my invention is to provide an improved feed valve device in which the above diihculty is overcome.

In the accompanying drawing, the single ligure is an elevational view, partly in section, of a feed valve device, embodying my invention.

`The feed valve device 1 comprises a casing having a piston chamber 4 containing a piston 5 and a valve chamber 6 containing a slide valve 7. The regulatingportion of the feed valve device comprises a flexible diaphragm 8, subject on one side to the pressure of an adjustable coil spring 9 and on the opposite side to the fluid pressure in chamber 10, and said diaphragm is adapted to control the operation of a regulating valve 11, subject to the pressure of a spring 12.

The supply piston 5 and slide valve 7 are contained in a removable bushing 13, adapted, when assembled in the feed valve casing l, to seal against a gasket 14 to form chambers 15 and 16, and at another point to seal against a gasket 17 to separate piston chamber 4 from chamber 16. a

The supply piston 5 and slide valve 7 are normally held in the position shown in the drawing by the pressure of the spring 41. After a predetermined degree of upward movement of said piston and slide valve, the piston engages the face 35 of a spring retainer 44, which is adapted to slide on the pin i 45. Further upward movement of said piston is then opposed by the combined pressures of springs 41 and 42.

rlfhe supply piston 5 is provided with a piston packing ring 18, adapted to prevent leakage varound the piston from valve chamber 6 to piston chamber 4. Connected to the piston 5 by a stem 19 is a cylindrical guide 20 having a spiral cut groove 21, guide 2() engaging surface 22 of the removable bushing 13. a

The cylindrical guide 20 has a chamber 23 containing pulled curled hair held in place between two perforated plates` 24 and 25. The plate 24 rests against a shoulder in the chamber 23, while the plate 25 is held in place by a spring ring 26 adapted to expand into an annular groove cut in the wall of chamber 23. y a

In the supply piston 5 is a chamber 28 connected to chamber 23 in the guide 20 by passage 29 and containing a choke plug 30 having screw-threaded engagement in said piston.

The choke plug 30 has a conical end through which a centrally disposed port 3l is provided which connects chamber 28 with a conical opening 32, which opens to piston chamber 4. Disposed at right angles to the port 31 and at right angles to each other are two cross ports 33 which open into the port 31.

rlwo slots 34, at right angles to each other, are provided in the piston face, so that when said piston engages the spring retainer face 35, communication between the port 32 in the pifston and the piston chamber 4 is not cut o The slide valve 7 is provided with a port 36 adapted, in the feed position of said slide valve, to re ster with a CQrreSpOnding port 37 in the sli e'valve seat.

In pratiomwith the brake pipe 3 charged to the adjustment of the regulating "spring 9, the pressure in diaphragm ,chamber 10, which chamber. is in constant communication with the brake pipe 3 by Way of passage 38 and chamber 16 around the removable bushing 13, operates the diaphragm 8, so as to permit the pressure of spring'12`to hold the regulating valve 11 closed. Fluid is supplied fromtheinainreservoir 2 to chamber 15 and thence through a plurality vof ports40, inthe removable bushing: 13, toslide valve chamber'6. Fluidat main reservoir pressure in chamber 15,l also iovvsthrough the pulled curled hair in chamber 23 of the piston guide 20, to passage`29 and thence through the ports 31, 33,43, and 32 into lpiston chamber 4, and since the regulating valve l1 is seated, the pressureslequalize ori the opposite sides of the supplypi'ston 5, 'thereby permitting the pressure of s ring 41 to hold said piston and slide valve? the position shown in the drawing; f

'Iy the pressure in the brakepipe 3 becomes less than 'the 'standard pressure carried in the brake pipe, as ldetermined by the adjustment ofthe regul'atingspring 9, said pressure being effective in chamber on` the'diaphragm 8,vv said dia hr'agm is operated by spring 9 to unseat the regulating valve 11. l vWhen the regulating valvel 1l 'is unseated, fluid under pressure in piston chamber 4 is vented through passage 39, past the regulating vvalve 11, into diaphragm chamber 10 and thence through passage 38 andfchamber 16to the brake pipe 3. The supply piston 5 isl then operated'b y the higher pressure of themain reservoir uid in valve chamber 6 to shift theslide valve 7, so that port 36 registers Wit'hport 37 in the slide valve seat. Fluid at main reservoir pressure in'valve chamber 6is thus permitted to flow through ports 36' and 37`into chamber l16 and thence to the brake pipe 3, charging said brake pipe.

. hen thel pressure in the brake pipe 3 and in the diaphragm chamber 10 is increased, by 110W through ports 36 and 37, 'to the standard pressure, the diaphragm 8 is operated by the pressurefin chamber 10, so as to permit the pressure of spring 12 to seat the regulating valvefll.V Fluid "at main yreservoir pressure inchamber 15 then vlovvs into piston chamber 4, Upon equalization of the fluid pressures on oppositefside'sfofthe piston y5, springs 41 and42foperate tofrefturn the piston 5 and slide valve 7 `to thepositionfshown in the drawing, in which the 'supply of Vfluid from the main reservoir 2 to the brake pipe 3 is cut olf.

By providing pulled curled hair in chamber 23 of the piston 5 through Which all fluid must pass be ore passing through the choke plug suspended moisture, o il va or or other foreign matter in the air suppl tends to be separated from said air, thereby protecting the choke plug 30 from becomin closed up or.V restricted. It will be notice that the choke plug 30 is provided with a plurality of ports through which fluid can flow from the chamber 28 to piston chamber 4, each port being ofthe same flow area as the port 43 betvveenthe conical opening 32 and, the 4Cross ports 32a, the port 43, being theport that determines the rate of flow. With this construction, in caseone or4 more ports becomer` clogged, therrate" of flow through the port 43y will remain. unimpaired so long as one of the ports 31 c1733 remain unclogged. The vconical endof the plug 3D, in lwhich are they live openings, alsoy to separate `foreign matter 'from the air, in that said foreign matter tends to lovv past the openings'33 andgazther in the chamber The conical opening 32,'which connects with ythe port 43, has also ybeen found tobeeflicient in preventing lcondensejd'oil from restrictin the port 43, in that the shape of said por permits a gradual expansion of the under pressure liowing `fromJ passage 43,` with the result that condensation is retardedpso as to occur 'near' the upper end of said'portl 32 instead of adjacent to the ort 43, whl'feat it Would graduallyclosesai: portt Having now described my invention, what I claim as new and desire to'secure byLetters Patent, is A 1. In a` feed valve device, a su pl Y valve forV controlling the supply 'ofv uid;I under pressure to an outlet, la piston and piston stem for operating said valve,`said piston having an axiallydsposedchamber o e enl to an axially diSpOSdpaSSge throne] said stem, anda removableplugin said, c lamber provided with a restrictedporttopermit Ythe restricted flow of'fluid through saldj passage andV said restricted portl to the chamber at the outer facev of 'said piston and meansoperated u on a reduction in outlet pressure for ventingV fluidfrom said,v last chamber. A l` 2. In a feed valve device, a su ply valve for controlling the supply of uid under pressure'toan outlet, a'piston and pist/,on stem for operating said valve, said piston having an axially disposed chamber open to an axiallyl disposed passage throu hsaj'id stem, andsaid stem having anfaxia posed chamber at its outer end open tofsiaid passage, a removable plug irrthei chamber in the pistony provided with'` aL restricted port, and an air strainer mountedinQthefchamber in. the Steier t@ Permit the Haw of: fluid my hand.

JOHN B. WRIGHT. 

